Crustaceans: Symbol of the Invulnerability of Christ If the idea of representing Christ the Warrior in the image of a dolphin occurred to Christians in the Roman period, as has been evidenced by Adhemar of Angouleme’s pontifical ring, how could their thinking not have been turned, with the same intentions, to the armoured fish, to the crustaceans which nature graced with defensive and offensive arms? (Fig I).